Die retaining devices



United States Patent [72] Inventors Lawrence V. Whistler, Sr.

259 Doncaster Road;

Lawrence V. Whistler, J r., 251 Doncaster Road, Kenmore, New York 14217 21 Appl. No. 717,606 [22] Filed April 1, 1968 [45] Patented Oct. 27, 1970 [54] DIE RETAINING DEVICES 5 Claims, 20 Drawing Figs.

[52] U.S. Cl 83/698 [51] Int. Cl B261 1/14 [50] Field of Search 83/690, 698, 699, 700'.85/8.8;287/1l5 [56] References Cited UNITED STATES PATENTS 2,245,676 6/1941 Johnson 83/698X 2,364,401 12/1944 Stellin v 83/698X 2,798,748 7/1957 Maurer 85/8.8X 3,137,l93 6/1964 Whistler et al 83/698X 3,269,238 8/1966 Whistler et al.... 83/698X Primary Examiner-James M. Meister Attorney-Shoemaker and Mattare ABSTRACT: The die retaining means includes a die receiving hole and a holding means which is a relatively rigid resilient disclike member having a plurality of spaced inner resilient portions for engaging and holding a die in position. Retainer means is disposed in abutting relationship with the holding means to retain it in operative position. in a first form of punch retaining means, a transversely movable holding pin has a sloping wedge surface engageable with a cooperating wedge surface on a punch. The holding pin is resiliently urged toward an associated punch, and a separate screw means is provided with a cam surface engageable with a cam surface on the holding pin for camming the holding pin into operative position. In a second form of punch retaining means, the punch receiving hole includes a counterbored threaded hole within which a split threaded retaining collar is threaded. The punch is provided with an intermediate tapered portion, and the split retaining collar has an annular contact edge for engagement with the intermediate portion of the punch whereby the retaining collar is expanded within its associated threaded hole to retain the parts in operative position.

Patented Oct. 27, 1970 I III 3,s35,se7

, gum n INVENTORS I IO LAWRENCE V. WHISTLER,SR.8|

LAWRENCE V. WH|STLER,JR.

%J/d Wm ATTORNEYS Patented Oct. 27, 1970 3,535,967

INVENTOR LAWRENCE V. WHISTLER, SR. 8: LAWRENCE V. WHISTLER, JR.

I BY% All ATTORNEYS Patented Oct. 27, 1970 Sheet 3 of3 INVENTORS LAWRENCE V. WHISTLER, SR. 81 LAWRENCE V. WHISTLER, JR.

ATTORNEYS DIE RETAINING DEVICES BACKGROUND OF THE INVENTION The present invention relates to devices for retaining punches and dies in operative relationship with respect to associated punch and die shoes as employed for punching holes in workpieces.

Many arrangements have been employed heretofore for holding punches and dies in operative position, such arrangements generally including set screws or resiliently biased members which engage within suitable notches provided in the punches and dies for holding them in operative position.

Many of the prior art arrangements for holding punches and dies in operative position are difficult to assemble and disassemble and mounting and dismounting of the punches and dies is a time-consuming operation.

Additionally, the arrangements as employed in the prior art often do not provide a means for accurately aligning the punches or dies with respect to the associated retainers, and furthermore the means for holding the punches and dies in operative relationship are subject to damage and breakage in use.

SUMMARY OF THE INVENTION The die retaining means of the present invention includes a holding means in the form of a relatively rigid resilient disclike member having a plurality of spaced inner portions which are adapted to engage and hold the die in operative relationship, this holding means being retained in operative position by abutting retainer means.

This type of holding means permits quick and easy assembly and disassembly of die means with respect to the die retainer, and additionally provides a positive holding force which assures that the die means will be properly held in operative position.

Furthermore, the die retaining means of the present invention may be employed a large number of times without excessive wear or breakage. Means is also provided for ensuring accurate alignment of the die with respect to the associated die retainer.

In a first form of punch retaining means according to the present invention, a laterally movable holding pin is provided having a wedge surface thereon which engages a cooperating wedge surface on a punch. On high production dies. it is necessary to have the punch head seated tightly against the punch retainer to eliminate any peening action. The cooperating wedge surfaces ensure that the punch head will be seated firmly against the associated punch retainer.

Additionally, in this form of the invention, a screw means is provided with a cam surface engageable with a cam surface on the holding pin whereby very strong positive locking force may be applied to the apparatus, and yet at the same time the screw means may be readily backed off to remove the punch when so desired. Means is also provided in this form of the invention for accurately aligning the punch with respect to the associated punch retainer.

In another form of punch retaining means according to the present invention. the punch receiving hole in the punch retainer is counterbored and threaded to receive a split retaining collar which is threaded within the threaded counterbored portion, this split retaining collar engaging a'tapered surface on an associated punch so that when the split retaining collar is tightened up, it will expand outwardly so as to be tightly held in operative position to ensure that the parts will remain in proper operative relationship. Means is also provided in this form of the invention for ensuring accurate alignment between the punch and the associated punch retainer.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top view illustrating a die retaining means according to the present invention mounted on an associated die shoe;

FIG. 2 is a sectional view taken substantially along line 2-2 of FIG. 1 looking in the direction of the arrows;

til

FIG. 3 is a sectional view taken substantially along line 3-3 of FIG. 1 looking in the direction of the arrows;

FIG. 4 is a plan view of the holding means employed in this form of the invention;

FIG. 5 is a top view of a tool employed with the present invention;

FIG. 6 is a front view of the tool shown in FIG. 5;

FIG. 7 is a vertical section through a punch retaining means according to the present invention;

FIG. 8 is a sectional view taken substantially along line 8-8 of FIG. 7 looking in the direction of the arrows;

FIG. 9 is a sectional view taken substantially along line 9-9 of FIG. 7 looking in the direction of the arrows;

FIG. 10 is a vertical section through a modified form of punch retaining means according to the present invention;

FIG 11 is a sectional view taken substantially along line 11-11 of FIG. 10 looking in the direction of the arrows;

FIG. 12 is a vertical section through a further modified form of punch retaining means according to the present invention;

FIG. 13 is a top view of an aligning pin employed in the structure shown in FIG. 12:

FIG. 14 is a front view of the aligning pin shown in FIG. 13',

FIG. 15 illustrates the structure shown in FIG. 12 with a shim inserted in operative relationship therewithin;

FIG. 16 is a top perspective view of the shim illustrated in the structure shown in FIG. 15;

FIG, 17 is a top perspective view of the split retaining collar utilized in the structure shown in FIGS. 12 and 15;

FIG. 18 is an enlarged view of a portion of the structure shown in FIGS. 12 and 15;

FIG. 19 is a vertical section through a modified form of die retaining means according to the present invention; and

FIG. 20 is a vertical section through still another form of die retaining means according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings wherein like reference characters designate corresponding parts throughout the several views, a first form of die retaining means according to the present invention is illustrated in FIGS. [-4 inclusive. As seen in these figures, a die retainer is indicated generally by reference numeral 30 and comprises a block of rigid material such as steel or the like having a first pair of dowel holes 32 formed therethrough for receiving dowels 34 therein as seen most clearly in FIG. 3, these dowels extending into suitable aligned holes 32' provided in an associated die shoe 36.

The die retainer is also provided with a pair of threaded holes 38 which are counterbored at the upper portion thereof as seen in FIG. 3 for receiving suitable retainer screws 40. This counterbored arrangement enables the die retainer to be either face mounted as illustrated in FIG. 3 or back mounted if so desired.

The die retainer includes a die receiving hole 50 disposed in the center portion thereof, this die receiving hole 50 being in communication with an enlarged counterbored hole portion 52. A holding means 56 is disposed within the enlarged hole portion 52 and isheld in operative position by retainer means in the form of a ring 60 which is pressed in or shrunk in to the hole 52 to retain the holding means 56 in operative position.

Referring to FIG. 4, the holding means 56 comprises a relatively rigid resilient member comprising a thin tempered spring steel or the like which is of substantially flat disclike configuration. Member 56 is provided with a plurality of radially extending cutouts or slots 64 dividing member 56 into a plurality of spaced portions 66 the inner surfaces of which are spaced to provide a central hole of slightly smaller dimension than the outer dimension of an associated die bushing whereby member 56 is adapted to engage and hold the die bushing in operative position within the die retainer.

Referring again to FIGS. 2 and 3, retainer ring 60 is provided with an inner upper beveled edge 70 which provides a relief means whereby the holding means 56 is adapted to flex in a downward direction as seen in these figures when a die bushing 72 is inserted into the operative relationship illustrated. It is apparent that in the operative position shown, the inner edges of portion 66 of member 56 will engage the outer surface of the die bushing and will hold it in operative position. A substantial amount of force is required to remove the die bushing, and accordingly the die bushing will be securely held in the operative position illustrated.

The holding means 56 is similar in construction and mode of operation to that shown in U.S. Pat. No. 3,269,238.

The die bushing 72 is provided with a hole 76 formed therethrough of any desired configuration such as round, square, or oblong and the like. The die shoe 36 is provided with a hole 78 formed therein which is aligned with the hole in the die bushing for receiving material from a workpiece associated with the die bushing. As seen in FIG. 2, a workpiece is illustrated by the phantom line 80, and a punch is indicated by the phantom line 82.

One or more washer type shims 86 of annular configuration may be inserted in the operative position shown so as to rest upon the upper face of the die shoe and to support the die bushing a predetermined distance above the die shoe as required. This enables additional grinding of the surface of the die bushing and lengthens the useful life thereof.

The die bushing is provided with a flat 90 on one side thereof, this flat cooperating with a corresponding flat 91 formed on an aligning pin 92 disposed within a transversely extending opening 94 provided in the die retainer. This aligning pin may be of the same construction as shown in U.S. Pat. No. 3,137,]93, and the intercooperation and alignment of the die bushing with respect to the associated die retainer is accomplished in the same manner as illustrated in detail in this latter-mentioned U.S. patent.

The die bushing is provided with a circumferentially extend ing groove 98 formed therein adjacent the upper end of the die bushing. This groove facilitates removal of the die bushing by means of the tool illustrated in FIGS. and 6 the tool 100 includes an elongated central portion 102. A first end portion 104 extends at an angle from the central portion 102 and terminates in two spaced portions 106 which extend substantially normally to the end portion 104. These spaced portions 106 include inwardly extending projections 108.

At the opposite end of the tool, the end portion 110 extends downwardly at an angle from the central portion 102 and ter' minates in a pair of spaced portions 112 which extend substantially normally to the end portion 110. Projections. 1 14 extend inwardly from each of the spaced portions 112.

Referring now to FIG. 3, the manner in which the tool is employed for removing the die bushing is clearly illustrated. As seen in this figure, the tool is positioned so that the projections 108 at one end thereof are disposed within generally diametrically opposite portions of the groove 98 formed in the die bushing, it being understood that the projections 108 are so spaced as to fit snugly within diametrically opposite portions of the groove. When the tool has been inserted into the operative position shown in FIG. 3, it is apparent that downward movement of the central portion of the tool in the direction of the arrow will cause the tool to pivot about the die retainer so as to raise the die bushing out of the die receiving hole in the die bushing.

The tool 100 is so designed that the left-hand end portion thereof as seen in the drawings is adapted to fit within a die bushing for removing a die bushing from an associated die retainer, and the opposite end portion of the tool is adapted to be utilized with a punch having a suitable groove formed therein.

Referring now to FIG. 19, a modified form of die retaining means is illustrated. The die retainer in this form of the invention is illustrated generally by reference numeral 120 and includes a lower elongated leg portion 122 having an elongated slot 124 formed therein for receiving suitable mechanical fastener means such as nut and bolt assemblies and the like for securing the die retainer to a cooperating die shoe.

The die retainer includes an upstanding portion 126 having a die receiving hole 128 formed therein which is in communication with a counterbored enlarged hole 130. A holding means 132 substantially identical with the holding means 56 previously described is disposed within hole and is held in place by a retainer ring 134 which may be suitably secured in the operative position shown. In this form of the invention, the holes 128 and 130 may be joined by a beveled portion 133 which provides a relief for the holding means to enable it to flex into the operative position illustrated in FIG. 19.

A die bushing 136 is provided with a central hole 138 formed therethrough which is aligned with a hole 140 formed in the portion 126 of the die retainer. A further hole 142 within the die retainer is adapted to direct pieces of a workpiece downwardly and outwardly of the die mechanism.

The die bushing is provided with a circumferentially extending groove 144 which is adapted to cooperate with the tool 100 previously described whereby the die bushing may be readily removed from the associated die retainer. It is apparent that this die bushing as well as the die bushing previously described may be readily inserted into the operative position simply by pushing it manually inwardly to the position shown, and may subsequently also be readily removed with the use of the tool.

Referring now to FIG. 20. still another form of die retainer means according to the present invention is illustrated. This die retaining means is similar in outward appearance to the die retaining means illustrated in U.S. Pat. No. 3.089376. The die retainer indicated generally by reference numeral is substantially cylindrical in outer configuration and includes a die receiving hole 152 which is in communication with an enlarged counterbored hole 154. A holding means 156 substantially identical to the holding means 56 previously described is held in operative position within hole 154 by a retainer ring 158 suitably held in the operative position illustrated. In this form of the invention, the die retainer includes a beveled portion 160 which provides a relief to permit the holding means to flex into the operative position illustrated A die bushing 162 is disposed within the die receiving hole in the die retainer and has a central hole 164 formed therethrough which is in communication with the hole 166 provided in the die retainer. A further hole 168 formed in the die retainer is in communication with hole 166 for directing pieces of a workpiece downwardly and outwardly of the die mechanism.

It is of course apparent that in each of the die retaining mechanisms herein disclosed, the holding means is of such a dimension that the inner portions thereof extend slightly mwardly of the adjacent die retainer portion so as to engage the outer surface of the die bushing to hold it in the operative positions illustrated.

As seen in FIG. 20, a die template is indicated by reference numeral 170, and a snap ring 172 is disposed within a circumferentially extending groove 176 for retaining the die mechanism in operative relationship on an associated template. The snap ring may be removed when desired, and groove 176 is adapted to cooperate with the tool previously described for readily removing the die bushing when required.

It should also be noted that suitable washer type shims may also be employed with the die retaining mechanisms illustrated in FIGS. 19 and 20 if so desired.

Referring now to FIGS. 7-9, punch retaining means according to the present invention is illustrated. The punch retainer is indicated generally by reference numeral 180 and is hardened and ground very accurately in the usual manner to fit snugly against an associated punch shoe 182 and receive a cooperating perforating punch. The punch retainer includes a punch receiving hole 184 which is in communication with a small drilled hole 186 which provides an air relief so that when a punch is being inserted or removed with respect to the retainer, the vacuum will be broken.

A conventional perforating punch 190 is illustrated in operative position within the punch retainer and includes a circumferentially extending groove 192 formed in the outer surface thereof. The upper end of the punch is provided with a flat 194 on one side thereof which engages a cooperating flat 196 formed on a tapered retaining pin 198 fitting within a transversely extending opening 200 formed in the punch retainer. This aligning pin arrangement is identical with that previously described and illustrated in US. Pat. No. 3,137,193.

The punch retainer is mounted upon the punch shoe in the usual manner, and as seen in FIG. 8, a pair of dowels 206 extend through aligned holes provided in the punch retainer and the punch shoe, and retainer screws 204 are threaded within suitable threaded holes provided either in the punch retainer or the punch shoe as the case may be.

The holding means in this form of the invention includes a holding pin 210 being substantially circular in cross-sectional configuration and being i'novably disposed within a laterally extending hole 212 formed in the punch retainer. The inner end of the holding pin includes a sloping wedge surface 216 which is adapted to engage a cooperating sloping wedge surface 218 formed on punch 190 as a part of a cutout 220 formed in the upper portion of the punch at the opposite side of the punch from the flat 194 previously described.

The upper portion of the holding pin 210 is provided with a straight groove 230 which snugly receives the lower end of a resilient spring plate 232, this spring plate being secured to the side of the punch retainer by a pair of screws 234. Since the lower end of the plate 232 fits snugly within the groove 230, the pin 210 is held against turning movement, and additionally, the spring plate urges the holding pin inwardly toward the operative position illustrated in the drawings.

As seen most clearly in FIG. 7, means for positively forcing the holding pin toward the punch includes a threaded hole 240 formed in the punch retainer and in communication with the laterally extending opening 212. A threaded screw 242 is received within this hole, and the lower edge of the hole may be upset at opposite sides thereof as indicated by reference numeral 244 to prevent the screw from being removed in a downward direction from the threaded hole. Nevertheless, these upset portions permit the screw 242 to be moved downwardly sufficiently such that the holding pin 210 may be moved to the right as seen in FIG. 7 to release the punch from the punch retainer.

The upper end of screiv 242 is provided with a generally frustoconical upper end portion 250 which is adapted to be received within a correspondingly shaped hole 252 formed in the undersurface of the holding pin 210. The upper portion of hole 252 is in communication with a drilled hole 254.

It is apparent that by threading the screw 242 upwardly as seen in FIG. 7, the cooperating cam surfaces defined by the frustoconical head portion 250 and the frustoconical hole 252 of the holding pin will cause the holding pin to be positively urged to the left as seen in FIG. 7 so as to cause the wedge surfaces 216 and 218 to cooperate with one another and force the punch tightly into the upper end of the punch receiving hole formed in the punch retainer.

On the other hand, when the screw 242 is moved downwardly from the position shown in FIG. 7, the holding pin 210 can be readily moved outwardly against the force of spring plate 232.

It is very important on high production dies to provide some means as the wedge surfaces of this form of the invention in order to ensure that the punch head is seated tightly against the punch retainer to eliminate any peening action. The punch may be removed from the operative position illustrated in FIGS. 7 and 9 by utilizing the right-hand end of the tool 100 shown in FIGS. and 6, the inwardly extending portions 114 of the tool fitting within diametrically opposite portions of the groove 192 in the punch, whereupon tilting movement of the tool is adapted to force the punch out of the punch retainer in the same manner in which the tool is utilized in connection with a die retainer.

It will be noted that the upper end of the punch as seen in FIG. 7 has a slight radius 260 formed on the edge portion thereof to facilitate insertion of the punch into operative position. When the punch is inserted into the operative relationship illustrated, the holding pin 210 will snap into place under the influence of the spring plate 232.

Referring now to FIGS. 10 and 11, a modification of the structure shown in FIGS. 7-9 inclusive is illustrated. This arrangement is substantially the same as that shown in FIGS. 7- --9, and similar parts have been given the same reference numerals primed. The only difference in this form of the invention is the manner in which the punch is aligned with respect tothe associated punch retainer.

Instead of providing the tapered pin arrangement as shown in FIGS. 7-9, a laterally extending hole 268 is provided which receives a steel pin 270 having a flat 272 on the inner end thereof. This steel pin is held against a master to initially obtain proper alignment of the pin, and then a body of epoxy resin 274 is extruded around pin 270 while it is held against a master in a fixture and hardened either by a short heat treatment or by air drying. This method of retaining the aligning pin in proper operative position eliminates the possibility of misalignment which may be caused by welding of the end of the pin in place.

An important consideration in connection with the structure shown in FIGS. 7-11 inclusive is the fact that the stripping load on the punch after it has pierced a hole in a workpiece and is being withdrawn is transferred through the cooperating wedge surfaces in such a manner that the screw members 242 or 242' are prevented from loosening. This is quite important since under high production conditions this prevents the components from vibrating loose.

Referring now to FIGS. l2-l8 of the drawings, a further modified form of punch retaining means is illustrated. The punch retainer 280 is suitably secured to a punch shoe 282 by the usual dowel and retainer screws as previously described. The punch retainer is provided with a punch receiving hole 286 ofa first diameter and a counterbored threaded hole 288 of a larger diameter in communication therewith.

A punch is indicated generally by reference numeral 290, the punch including a first perforating portion 292 of reduced diameter and a second enlarged diameter portion 294, these two portions of the punch being interconnected by a tapered intermediate portion 296.

The punch has a flat 300 formed thereon at the enlarged diameter portion 294 thereof, and an aligning pin 302 is disposed within a suitable transversely extending opening in the punch retainer for engaging the flat and holding the punch in the proper aligned position.

Referring to FIGS. 13 and 14, the aligning pin 302 is illustrated in detail. The pin is provided with a diameter which is substantially the same as that of the opening within which it is disposed so that the aligning pin is adapted to be snugly received within the associated opening. The pin is provided with a flat 304 along one side thereof which extends from a first end portion 306 thereof to a point spaced a small distance from the opposite end 308 thereof.

When the aligning pin is inserted in operative position within the associated opening, the flat 304 lies in a plane which extends substantially parallel to a plane passing through the longitudinal axis of the punch receiving hole whereby the aligning pin serves to accurately position the punch in the same manner as illustrated in US. Pat. No. 3,137,193.

A split retaining collar is indicated generally by reference numeral 320, and as seen most clearly in FIG. 17 is provided with threads 322 on the outer surface thereof. The retaining collar includes a longitudinally extending slot 324 formed therethrough, and one or more radially extending slots 328 may be provided in one end thereof for engagement with a suitable wrench to enable the retaining collar to be moved into and out of operative position.

Reference numeral 330 indicates a tough plastic locking element which is mechanically retained in the fastener threads. This fastening element may comprise a NYLOK selflocking fastener manufactured by The Nylok Company, Division of United Shoe Machinery Corporation, Paramus, New Jersey 07652. This expanding material wedges into the threads and prevents the retaining collar from working loose after inserted in the operative position shown in FIG. 12.

FIG. 18 illustrates the retaining collar in operative position within the threaded bore 288 of the punch retainer and in engagement with the punch. The upper inner contact edge 332 of the retaining collar is rounded as illustrated in FIG. 18 and is adapted to engage with the tapered intermediate portion 296 of the punch.

When the punch is inserted in the operative position shown in FIG. 12, the retaining collar 320 is threaded upwardly within the threaded bore 288 of the punch retainer until the inner edge 332 of the retaining collar engages the portion 296 of the punch. The retaining collar is then spread apart so as to be wedged tightly in the operative position shown in H6. 12 thereby expanding and locking itself into place.

As seen in FIG. 15, a washer 334 is adapted to be inserted in operative position between the upper end of the punch and the associated punch retainer. This washer as seen in FIG. 16 may be of substantially disclike configuration and provides means for enabling the end of the punch to be sharpened while retaining the punch to its original face length.

Here again, in this form of the invention, the punch may be readily inserted and removed with respect to the punch retainer, and the components are held in positive relationship with respect to one another while in use.

As this invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, and since the scope of the invention is defined by the appended claims, all changes that fall within the metes and bounds of the claims or that form their functional as well as conjointly cooperative equivalents are therefore intended to be embraced by those claims.

We claim:

1. Die retaining means comprising a die retainer having a die receiving hole formed therein, holding means supported by said die retainer, said holding means being formed of relatively rigid resilient material and comprising a substantially flat disclike means, the inner area of which defines a plurality of spaced portions of resilient construction, the inner surfaces of said spaced portions defining a central opening of slightly smaller dimension than a die to be received therein, retainer means supported by said die retainer and engaging said holding means for retaining the holding means in position relative to said die retainer, and opposed supporting surface means on opposite sides of said holding means enabling flexure of said holding means in one direction only for snugly receiving and holding a die, said holding means resting in flat contact with said supporting surfaces throughout substantially its entire extent.

2. Apparatus as defined in claim 1 including a relieved portion on one of said surface means disposed adjacent said holding means for permitting said holding means to flex in said one direction.

3. Apparatus as defined in claim 1 including aligning means for properly aligning said die retainer and an associated die.

4. Apparatus as defined in claim 1 including a die disposed within said die receiving hole, and a shim disposed in contact with the inner end of said die.

5. Die retaining means comprising a die retainer having a die receiving hole formed therein, holding means supported by said die retainer, said holding means being formed of relatively rigid resilient material and comprising a substantially flat disclike means, the inner area of which defines a plurality of spaced portions of resilient construction, the inner surfaces of said spaced portions receiving an associated die and being adapted to flex in one direction for snugly receiving and holding a die, and retainer means supported by said die retainer and engaging said holding means for retaining the holding means in position relative to said die retainer. said retainer means including a beveled edge portion defining a relieved portion disposed adjacent said holding means for permitting said holding means to flex in said one direction. 

